On Sun, 12 Feb 2012 20:32:40 -0600, "Doug"
wrote:

What is the easiest way to do this? After I clean it, is a sealer
really worth while?

I've used sulfamic acid (TileLab brand) to clean (dilute more than
instructed).

I see they now have:

"Ready-to-use, non-abrasive cleaner and degreaser for everyday
cleaning of grout and tile. Cuts through grease, soap scum, dirt and
food stains. Easy, no-rinse formula."

I've not used the spray cleaner. The site also has a sealer.

http://www.custombuildingproducts.com/ProductCatalog/newcare/newcleaners/GroutTileCleaner.aspx?user=arc&lang=en

Sealers are good. A few days after my tile floor went in, someone
spilled red paint on the grout. It cleaned up nicely without much
effort. Luckily I had already sealed it. That sealer may not be
available today as it caused medical problems for the users.